Skip to main content
OS Authority

Compress a photo or signature to 20 KB

Exam, job and government portals often want a signature or small photo under 20 KB. Add your picture and get a JPG that fits, in a few seconds.

Your images are processed on this device and never uploaded. We don't see, store or log your files.

Common sizes

How it works

  1. Tap Choose files, or Take photo on a phone, and add JPG, PNG or WebP images.
  2. Tap Compress images. Each image is saved as a JPG under 20 KB.
  3. Download the images one by one or as a ZIP, or tap Share.

Why compress here

Your photos never leave your phone or computer, and camera location data (EXIF) is not copied into the new files. It is free, with no watermark and no account, and you can compress many images at once.

What fits in 20 KB

At good quality a photo of about 400 × 500 pixels fits in 20 KB, which is plenty for the small photo box on most forms. A signature on white paper compresses far better: a clear 600 × 250 pixel scan is usually 10–15 KB. A 12-megapixel phone photo (4032 × 3024, around 3 MB) is scaled down to about that size automatically.

Tips for signatures

Sign in black or dark blue ink on plain white paper, photograph it in daylight without shadows, and crop close to the signature before compressing. Less empty paper means more of the 20 KB goes to the ink, so the lines stay sharp.

Frequently asked questions

My form also asks for exact pixels. What should I do?

Crop and resize to those pixels first with the Crop image or Resize image tool, then compress here. The pixels you set stay the same unless they can't fit in 20 KB.

Why is the result smaller than 20 KB?

The tool keeps the best quality that stays under the limit, and quality goes in steps, so the file usually lands a little below 20 KB. That is expected and safe for uploads.

Is 1 KB 1,000 or 1,024 bytes?

Sites count it both ways. We aim for 1,000 bytes per KB, so a 50 KB file here is at most 50,000 bytes and also passes a form that counts 1,024 (51,200 bytes).

Are my images uploaded?

No. Everything happens in your browser on your own device.

Related tools